SEQUENTIAL-ANALYSIS OF REDUCING OLIGOSACCHARIDES BASED ON A CHEMICAL-REACTION USING 8-AMINO-2-NAPHTHALENESULFONIC ACID

A method for the sequential analysis of reducing sugars has been devel oped based on repetition of the following procedures: 1) derivatizatio n of a reducing oligosaccharide with 8-amino-2-naphthalenesulfonic aci d (ANS) to produce a Schiff base, 2) reduction of the base with sodium cyanoborohydride, 3) methoxycarbonylation of the secondary amino grou p, 4) cleavage of the glycoside bond next to the reducing end, through intramolecular acid hydrolysis by the action of a sulfonic acid group of the ANS derivative, 5) identification of the liberated reducing en d by high-performance liquid chromatography (HPLC), and finally 6) rec overy of the resultant oligosaccharide fragment from the cleavage reac tion mixture. A satisfactory yield in the cleavage reaction and a quan titative recovery of the oligosaccharide fragments were obtained when the cleavage reaction of the ANS derivative was carried out at 140 deg rees C for 30 min in dioxane-dimethyl sulfoxide (7:3). The method was successfully applied to the sequential analysis of some reducing di- a nd trisaccharides.